A tree top which fell over a power line and bent a cross-arm brace on the hydro pole caused a two-hour power outage in Queen Charlotte lSaturday Dec. 1, says BC Hydro spokesperson Bob Gammar.The outage affected about 600 customers, Mr. Gammar said.It also knocked out the memory board on the heating system at Queen Charlotte Secondary school, said school district maintenance supervisor Paul Allen. The lack of heat meant school was cancelled for students on Monday. The system was fixed by the next day, Mr. Allen said.At the north end, one of the diesel generating units in Masset has been having an intermittent problem which has led to power failures, including a brief episode the morning of Nov. 28.Mr. Gammar said power was out for all customers in Old Massett, Masset and Port Clements for between five and ten minutes.Mr. Gammar said Hydro crews are still trying to figure out what is causing the equipment failure.Some Observer readers told us they want to know what causes our frequent power failures, and are having a hard time getting the information from the BC Hydro website.Mr. Gammar recommends phoning BC Hydro's 1-888-POWERON number and asking the customer agent what happened.He also reminds islanders that surge protectors are advisable for computer equipment. If the power goes out, islanders should turn off any sensitive equipment so it doesn't get flooded with power when the electricity comes back on, he added.There are more outage tips on the BC Hydro website at www.bchydro.com, Mr. Gammar said.